On thru-hikes and other long distance treks, the number one catagory in which people over pack in is clothing. Living outside is not like living in everyday life; fashion and clean clothing means nothing. With the right clothing system, it should be no more than 5 lbs -- and thats pushing it. This is how we broke it down for our AT hike, and the formula we will use next year for the PCT:
There should be four different catagories, baselayer, warm hiking, cool hiking, and camp clothing.
2 pairs of hiking socks (smartwool of course)
lightweight down jacket
lightweight wind jacket
Set of merino wool baselayers
extra set of underwear
dedicated camp sock (usually a thicker pair)
We found that hiking in spandex was really the best way to go. Since they are tight, they help prevent muscle fatigue, dry quickly when they get wet. For long distance hiking, rain gear is just unnecessary. You WILL get wet if you're living outdoors, and when that happens, throwing on a rain jacket will just make you hot and sweaty. The best thing to do is have something that will dry quickly and have something warm and cozy to change into later on. While spandex itself does not dry fast (the fabric) when its worn the body heat will dry it out rapidly. For cold days, a pair of rain pants will take the heat from your legs and trap it, providing warmth. So while it is a pair rain pants, they are used more for snowy/cold/windy weather. The windjacket provides protection from that biting cold that the wind gives you. For recommendations on brands and pieces, just ask away! I could go on for hours about this, so feel free to ask any questions you may have.
Like I tell anyone I help out, these are all our recomendations, and everyones trip is different and should be treated thusly. Hike your own hike! (just take our suggestions into consideration)